Exception Handling / Error Handler in C++

Exception Handling provides a mechanism to detect and report an exceptional circumstance, so that corrective action can be taken to set right the error occurred. Error Handler in C++ consists of three major keywords namely try, throw and catch. The "try" block is a set of code which generates an exception which is thrown using the "throw" statement. The "catch" block is used to catch the exception and handles it appropriately.

Throw point

Function that causes an exception.

try block

Invokes a function that contains an exception.

catch block

Catches and handles the exception.

Example :

#include <iostream.h> int main() { int x,y; cout << "Enter values of x::"; cin >> x; cout << "Enter values of y::"; cin >> y; int r=x-y; try { if ( r!=0) { cout << "Result of division is x/r:: " << x/r << "\n"; } else { throw ( r); } } catch( int r) { cout << "Division by zero exception:: value of r is::" << r << "\n"; } cout << "END"; return 0; }

Result :
In the above example, when the value "x" is divided by "0" an exception is thrown. Using the "catch" statement the exception is caught. This is the Error Handler System in C++.